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Fencer Vulns
medium 6.5

CVE-2021-36976 json

libarchive 3.4.1 through 3.5.1 has a use-after-free in `copy_string` (called from...

published 2021-07-20 5 y ago modified 2026-11-02 6 d ago also EUVD-2021-23552 , JLSEC-2025-234

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

libarchive 3.4.1 through 3.5.1 has a use-after-free in copy_string (called from do_uncompress_block and process_block).

Patch / fix

  • julia LibArchive_jll 3.7.4+0
  • splunk universal_forwarder 8.2.12, 9.0.6
  • apple ipados 15.4
  • apple iphone_os 15.4
  • apple macos 12.3
  • apple watchos 8.5
  • libarchive Debian 14, Debian 13, Debian 12 3.6.0-1

debian advisories DEBIAN-CVE-2021-36976

  • libarchive Ubuntu 20.04 LTS 3.4.0-2ubuntu1.1
  • libarchive Ubuntu 22.04 LTS 3.5.2-1ubuntu1

ubuntu advisories UBUNTU-CVE-2021-36976

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libarchive SLE Real Time 15 SP2, SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3 +4 more 3.4.2-150200.4.3.1
  • libarchive SLE Module for Development Tools 15 SP4, SLE Module for Basesystem 15 SP4, openSUSE Leap 15.4 3.5.1-150400.3.3.1

suse advisories SUSE-SU-2022:0944-2SUSE-SU-2022:1930-1SUSE-SU-2022:0944-1

  • bsdtar openSUSE Tumbleweed 3.6.0-1.1
  • libarchive openSUSE Leap 15.3 3.4.2-150200.4.3.1

opensuse advisories openSUSE-SU-2024:11894-1openSUSE-SU-2022:0944-1

  • libarchive Alpine 3.14, Alpine 3.13 3.5.3-r0
  • libarchive Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 3.6.0-r0

alpine advisories ALPINE-CVE-2021-36976

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libarchive CBL-Mariner 2.0 3.6.0-1

azure linux advisories AZL-6614

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • libarchive Arch Linux 3.6.1-1

arch linux advisories AVG-2176

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-36976 updated cvss 6.5

libarchive: use-after-free in copy_string()

  • Red Hat Enterprise Linux 6 libarchive Red Hat Enterprise Linux 7 bsdtar, bsdcpio, libarchive Red Hat Enterprise Linux 8 bsdtar, libarchive Red Hat Enterprise Linux 9 bsdtar, libarchive
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
31 d ago

Exploit prediction

2.84% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia LibArchive_jll
<3.7.4+0
3.7.4+0

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.